— Is it my age ______the boss minds?—I’m afraid so. He will consider ______ necessary to have an experienced assistant.
The research is so designed that once________nothing can be done to change it.
Visitors________not to touch the exhibits.
It is known to all that________you exercise regularly, you won't keep good health.
—What would you do if it________tomorrow? —We have to carry it on, since we've got everything ready.
We all know how difficult it is for all of us to eat better, exercise more, and sleep enough________we know we should.